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Biomedical subjects

S Chandran

Publications and source records attributed to S Chandran.

At least 19 recordsLinked to original sources
PubMed2001

A role for oligodendrocyte-derived IGF-1 in trophic support of cortical neurons.

Neurons and glia interact in the development of mammalian central nervous systems and in the maintenance of stable myelinated axons. Recent evidence suggests a role for oligodendrocytes in providing trophic support for neurons during development and in the mature nervous system. This work prompted us to study oligodendrocyte influences on neuronal survival and death in vitro. Rat embryonic cortical neurons were co-cultured with purified oligodendrocytes at different developmental stages and separately with oligodendrocyte-conditioned medium. Neuronal survival was measured by immunocytochemistry and 3H-GABA uptake. Neurons show a marked increase in survival when co-cultured directly with oligodendrocyte precursors (OPCs) and differentiated oligodendrocytes. Neurons cultured in the presence of OPCs separated by a permeable membrane and those cultured in medium conditioned by oligodendrocytes also show a significant increase in survival. Medium conditioned by differentiated oligodendrocytes provides a greater survival effect than medium conditioned by OPCs. Neutralising antibodies to IGF-1, but not to other candidate trophic factors, block the soluble survival effect of oligodendrocytes. Cells of the oligodendrocyte lineage produce IGF-1 and recombinant IGF-1 promotes neuronal survival under identical conditions. This study provides evidence that OPCs and differentiated oligodendrocytes support neuronal survival by both contact-mediated and soluble mechanisms and that IGF-1 significantly contributes to this effect.

Animals↗
PubMed2001

Peripheral blood level alterations of TIMP-1, MMP-2 and MMP-9 in patients with type 1 diabetes.

AIM: To determine the plasma levels of enzymes and inhibitors involved in extracellular matrix turnover in patients with Type 1 diabetes with normal renal function. METHODS: Plasma levels of matrix metalloproteinases 2 and 9 (MMP-2, MMP-9) and tissue inhibitor of metalloproteinase 1 (TIMP-1) were measured in 43 Type 1 diabetic subjects and age- and sex-matched controls. RESULTS: No significant difference in plasma MMP-2 between diabetic patients and controls was observed. MMP-9 was detected in the plasma of 15 diabetic patients (35%), but undetectable in all control subjects (P < 0.015). Plasma TIMP-1 concentrations were significantly elevated (P < 0.001) in diabetic patients compared to controls. There was no correlation observed between MMP-2, MMP-9 and TIMP-1 and similarly between MMP-2, MMP-9 and TIMP-1 and age, duration of diabetes, blood pressure and glycated haemoglobin (HbA1c). CONCLUSIONS: This study has demonstrated alterations in several plasma extracellular matrix modulators in the absence of significant vascular disease.

Adolescent↗
PubMed2000

The preparticipation athletic evaluation.

A comprehensive medical history that includes questions about a personal and family history of cardiovascular disease is the most important initial component of the preparticipation athletic evaluation. Additional questions should focus on any history of neurologic or musculoskeletal problems. A limited physical examination should emphasize cardiac auscultation with provocative maneuvers to screen for hypertrophic cardiomyopathy. This condition is the most common cause of sudden death in young male athletes. Other components of the physical examination include an evaluation of the spine and extremities. Screening tests such as electrocardiography, treadmill stress testing and urinalysis are not indicated in the absence of symptoms or a significant history of risk factors. Specific conditions that would exclude or limit athletic participation include hypertrophic cardiomyopathy, long QT interval syndrome, concussion, significant knee injury, sickle cell disease and uncontrolled seizures. Overall, about 1 percent of athletes who are screened are completely disqualified from sports participation.

Adolescent↗
PubMed2000

New Ultraviolet spectrophotometric method for the estimation of nimesulide.

Two simple and accurate ultraviolet (UV) spectrophotometric methods with better detection range for estimation of nimesulide in pure form and in solid dosage form were developed in the present studies using 50% v/v and 100% v/v acetonitrile as the solvent system. The linearity range of nimesulide in both the methods was found to be 10-50 micrograms/ml at a lambda max of 300 nm. The linear regression equations obtained by the least-square regression method are Abs = 1.33 x 10(-1).Conc + 1.89 x 10(-1) in 50% v/v acetonitrile and Abs = 1.05 x 10(-1).Conc + 1.14 x 10(-1) in 100% v/v acetonitrile. The detection limit as per the error propagation theory was found to be 0.46 microgram/ml and 1.04 micrograms/ml, respectively, in 50% v/v and 100% v/v acetonitrile. The developed methods were employed with high degree of precision and accuracy for the estimation of total drug content in three commercial tablet formulations of nimesulide. The results of the analysis were validated statistically and by recovery studies.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2000

Fetal acalvaria with amniotic band syndrome.

A case of amniotic band syndrome (ABS) presenting with acalvaria is reported. ABS includes a spectrum of non-genetic anomalies, varying from simple digital band constriction to major craniofacial and visceral defects, and even fetal death. Acalvaria is a rare congenital malformation characterised by the absence of the dome-like superior portion of the cranium comprising the frontal, parietal, and occipital bones and dura mater, in the presence of a normal skull base and facial bones with complete cranial contents. No two cases are the same. Acrania or absence of the flat skull bones with disorganised cerebral hemispheres have been reported in the presence of amniotic bands. ABS is an aetiological factor in acalvaria. Appropriate counselling for affected families needs to be given after prenatal diagnosis.

Amnion↗
PubMed1998

A new method for the rapid and long term growth of human neural precursor cells.

A reliable source of human neural tissue would be of immense practical value to both neuroscientists and clinical neural transplantation trials. In this study, human precursor cells were isolated from the developing human cortex and, in the presence of both epidermal and fibroblast growth factor-2, grew in culture as sphere shaped clusters. Using traditional passaging techniques and culture mediums the rate of growth was extremely slow, and only a 12-fold expansion in total cell number could be achieved. However, when intact spheres were sectioned into quarters, rather than mechanically dissociated, cell cell contacts were maintained and cellular trauma minimised which permitted the rapid and continual growth of each individual quarter. Using this method we have achieved a 1.5 million-fold increase in precursor cell number over a period of less than 200 days. Upon differentiation by exposure to a substrate, cells migrated out from the spheres and formed a monolayer of astrocytes and neurons. No oligodendrocytes were found to develop from these human neural precursor cells at late passages when whole spheres were differentiated. This simple and novel culture method allows the rapid expansion of large numbers of non-transformed human neural precursor cells which may be of use in drug discovery, ex vivo gene therapy and clinical neural transplantation.

Automation↗
PubMed1998

Regional potential for oligodendrocyte generation in the rodent embryonic spinal cord following exposure to EGF and FGF-2.

The origin of oligodendrocytes in the developing rodent spinal cord has not been fully established, with some evidence that oligodendrocyte progenitors arise exclusively from the ventral neuroepithelium, other studies suggesting that both halves of the spinal cord have oligodendrogenic potential. One way of exploring this issue is to study more primitive oligodendrocyte precursors. Although specific markers are not available, their presence may be inferred using mitogens such as EGF and FGF-2, which stimulate the proliferation of immature neuroepithelial cells, and subsequently studying their differentiation into lineage restricted cells. We used this approach to assess whether the dorsal embryonic rodent spinal cord has the intrinsic potential for oligodendrocyte formation at E14. We confirm that significant numbers of oligodendrocytes and their immediate (A2B5+) precursors are present only in the ventral spinal cord of the E14 rodent, but following exposure to EGF and FGF-2, significant numbers of oligodendrocytes and A2B5+ precursor cells also develop from isolated E14 dorsal derived cells without interaction from the ventral spinal cord. In addition, bromodeoxyuridine studies demonstrate that isolated dorsal derived cells proliferate and express A2B5 following exposure to EGF and FGF-2. The observation that from E14, the dorsal cord already has latent oligodendrogenic potential provides an alternative mechanism for oligodendrocyte formation to ventro-dorsal migration of oligodendrocyte precursors.

Animals↗
PubMed1998

A trial of baby check scoring system to identify high-risk infants in a polyclinic in Oman.

The baby check score card was used in a busy polyclinic to identify babies with different grades of illness attending as out-patients. A total of 90 paediatric patients in the age group 1 to 6 months were screened during February to June 1995. These patients were seen by the junior physicians. They filled in the score card and graded the illness, as they perceived, into well or mild, moderate, and severe. The scores, as described by the original authors, were then assigned to the various signs and symptoms recorded in the score card, by the investigators. The total scores obtained were correlated with the grades of illness (grade 1-well or mild, grade 2-moderate, and grade 3-severe). The scores ranged from 0 to 41. Forty-three cases were well or mildly ill; 41 moderately ill; and six seriously ill. The scores generally correlated with the grades of illness. Those with lower scores had milder illness and were sent home with reassurance. Six cases who were seriously ill all scored over 20 and were referred for tertiary care. The scoring system appeared to be fairly accurate in identifying high-risk infants. It could be used as a valuable tool for screening infants for severity of illness with reasonable accuracy in our set-up.

Ambulatory Care Facilities↗
PubMed1997

Recent trends in drug delivery systems: liposomal drug delivery system--preparation and characterisation.

Liposomes are potential drug carriers for variety of drugs, therapeutic proteins and diagnostic agents. Drug entrapment ability of liposomes makes it more useful in targetting of drugs to specific site within the body. Major components of liposomes include lipids, water, drugs, electrolytes, antioxidants, preservatives and viscosity inducing agents. Considering the widespread use of liposomes in drug therapy and problem of physico-chemical instabilities of liposomes, this article aims at giving an insight into various methods of preparation of different types of liposomes like, unilamellar and multilamellar vesicles, consideration of some critical aspects of manufacturing processes and the characterization of liposomal drug delivery system in reference to vesicle size distribution, determination of residual organic phase in the phospholipid bilayer system, per cent drug encapsulation and identification.

Drug Carriers↗
PubMed1990

Chondroid syringoma-scalp. A case report.

A case of chondroid syringoma of scalp is reported. The case is of particular interest because of repeated recurrence with bone and dural infiltration.

Adenoma, Sweat Gland↗